NIST researchers have found that the flexible plastic membrane on which wearables would be built might work better if the membrane had microscopic holes in it. (Credit: Reyes-Hernandez/NIST)

A research team has developed a way to build safe, nontoxic gold wires onto flexible, thin plastic film. Their demonstration potentially clears the path for a host of wearable electronic devices that monitor health. The finding could enable the creation of electronics that are flexible enough to be worn comfortably on or even inside the human body — without exposing a person to harmful chemicals in the process — and that will last long enough to be useful and convenient.

Gold is a good option for wearables because, unlike most metals, it does not corrode, and it has the added value of being nontoxic. But it’s also brittle. If you bend it, it tends to crack, potentially breaking completely — meaning thin gold wires might stop conducting electricity after a few twists of the body.

The researchers patterned gold electrodes onto commercially available porous polyester membrane. When the plastic was twisted a few times, the electrodes, which covered numerous pores as they crisscrossed the surface, still conducted electricity. The next steps will be to test changes in conductivity over the long term after many bends and twists and to build a sensor out of the electrode-coated membrane to explore its real-world usability.